684252490581 has 36 divisors (see below), whose sum is σ = 1086684598636. Its totient is φ = 414583868160.

The previous prime is 684252490577. The next prime is 684252490583. The reversal of 684252490581 is 185094252486.

684252490581 is a `hidden beast` number, since 6 + 8 + 4 + 2 + 52 + 4 + 9 + 0 + 581 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 17441428356 + 666811062225 = 132066^2 + 816585^2 .

It is not a de Polignac number, because 684252490581 - 2² = 684252490577 is a prime.

It is a super-2 number, since 2×684252490581² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (684252490583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3941055 + ... + 4111011.

Almost surely, 2^684252490581 is an apocalyptic number.

It is an amenable number.

684252490581 is a deficient number, since it is larger than the sum of its proper divisors (402432108055).

684252490581 is a wasteful number, since it uses less digits than its factorization.

684252490581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173682 (or 173668 counting only the distinct ones).

The product of its (nonzero) digits is 5529600, while the sum is 54.

The spelling of 684252490581 in words is "six hundred eighty-four billion, two hundred fifty-two million, four hundred ninety thousand, five hundred eighty-one".